1. Field of the Invention
The present invention relates to a tilting hinge, and more particularly, to a tilting hinge especially suitable for use with an office automation (OA) apparatus such as wordprocessor, personal computer or similar of laptop battery-operated portable type and notebook-sized type including a covering panel display and an apparatus main body to connect the covering panel display openably and closably to the main body and support the covering panel display tiltably.
2. Description of the Prior Art
A typical one of well-known tilting hinges of this type comprises or a bracket consisting of a mount plate portion for fixation to a main body of an OA apparatus and a bearing plate portion bent at a right angle in relation to the mount plate portion and in which a bearing hole is formed; a rotating shaft consisting of a mount portion for fixation to a covering panel display of the OA apparatus, large-diameter portion and an externally threaded small-diameter portion supported rotatably in the bearing hole of the bearing plate portion, the mount portion, large- and small-diameter portions being contiguous axially of the rotating shaft; a first friction plate or washer provided between the large-diameter portion of the rotating shaft and one side of the bearing plate of the fixture and having formed in the center thereof a hole in which the small-diameter portion of the rotating shaft is inserted; a second friction plate provided in engagement with the other side of the bearing plate and having formed in the center thereof a hole in which the small-diameter portion of the rotating shaft is inserted; a spring washer provided in engagement with the second friction plate and having formed in the center thereof a hole in which the small-diameter portion of rotating shaft is inserted; a lock washer provided in engagement with the spring washer and having formed in the center thereof a hole in which the small-diameter portion of the rotating shaft is inserted; and a locking nut screwed on the external thread on the small-diameter portion of the rotating shaft to press the lock washer to the spring washer.
In this conventional tilting hinge, however, there is some clearance between the rotating shaft and the inner wall of the hole in the lock washer. Because of this clearance, the lock washer is caused to move somehow in the rotating direction of the rotating shaft or bearing plate portion rotated alternately forward or reversely as the covering panel display is opened and closed. Thus, the lock washer will be loosened when the covering panel display has been operated repeatedly for a long time, resulting in the initial friction torque being reduced so that the panel display cannot be held at a desired opened angle.